title: Abnormal proteins enhance stress-induced cell death.
abstract: The effect of abnormal proteins on cell viability was studied using artificially cleaved polypeptides. Escherichia coli methionyl-tRNA synthetase (MetRS) consists of two distinct domains and its activity is essential for cell viability. The polypeptide chain was split by linker insertion and expressed as two fragments. Two pairs of polypeptides, one split within the N-terminal domain and another at the junction of the two domains retained aminoacylation activity. The in vitro activities of these split mutants were enhanced by the presence of chaperonin, GroESL. However, cells containing these split polypeptides became sensitive to conditions that induce GroESL. The results of this work suggest that an abnormally generated protein can cause cell death under stressful conditions.
authors.affiliation: Department of Biology, Sung Kyun Kwan University, Kyunggido, Korea.
authors.forename: S J
authors.initials: SJ
authors.lastname: Kim
authors.forename: S
authors.initials: S
authors.lastname: Kim
mesh_terms: D000890:Anti-Infective Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000494:pharmacology*; D018833:Chaperonins / Q000737:chemistry / Q000235:genetics / Q000494:pharmacology; D004795:Enzyme Stability; D004926:Escherichia coli / Q000187:drug effects* / Q000201:enzymology / Q000254:growth & development; D024841:Fluoroquinolones; D008718:Methionine-tRNA Ligase / Q000737:chemistry / Q000235:genetics / Q000494:pharmacology; D008958:Models, Molecular; D009154:Mutation; D015242:Ofloxacin / Q000494:pharmacology; D010446:Peptide Fragments / Q000737:chemistry / Q000235:genetics / Q000494:pharmacology; D011487:Protein Conformation; D015363:Quinolones / Q000494:pharmacology
chemical_list: D000890:Anti-Infective Agents; D001426:Bacterial Proteins; D024841:Fluoroquinolones; C097970:GroESL protein, Bacteria; D010446:Peptide Fragments; D015363:Quinolones; D015242:Ofloxacin; D018833:Chaperonins; D008718:Methionine-tRNA Ligase; C061363:sparfloxacin